Here is the full list of all 27 Rock Zombie achievements.
Unlock all achievements
Complete the game with Sasha
Complete the game on Hardcore difficulty without using any Continue
Unlock all of the Zombie Museum items
Kill 100 Marines
Kill 5000 Zombies
Complete the game with Crystal
Get the achievements 'Rock & Roll (Gold)', 'Heavy Metal (Gold)', Black Metal (Gold)' and 'Death Metal (Gold)
Perform 50 Heavy Metal combos
Perform 30 Black Metal combos
Perform 20 Death Metal combos
Kill 50 Marines
Kill 200 Spiders
Complete the game with Zoe
Perform 10 Black Metal combos
Perform 5 Death Metal combos
Kill 25 Marines
Kill 500 Zombies
Kill 2500 Zombies
Kill 50 Spiders
Kill 100 Spiders
Destroy 50 explosive items
Destroy 100 explosive items
Perform 10 Rock & Roll combos
Perform 50 Rock & Roll combos
Perform 10 Heavy Metal combos
Destroy 25 explosive items